Research

Dye-nanocrystal systems play a crucial role in advancing photovoltaics, photocatalysis, and spintronics technologies. The optimization of these devices demands a deep understanding of electron transfer and energy dynamics at the molecular level. Our research focuses on designing diverse hybrid systems by coupling organic and inorganic dyes with colloidal metal oxide nanocrystals. Through steady- state spectroscopy, we investigate dye binding mechanisms and subsequent quenching effects of these systems. We then employ ultrafast pump-probe spectroscopy to reveal the temporal evolution of electron and energy transfer processes. By systematically modifying key parameters—including nanocrystal composition, morphology, and surface chemistry, as well as dye structure and concentration—we can precisely tune the systems dynamics through controlled manipulation of binding characteristics, electronic coupling, and molecular aggregation.

How are excess electrons solvated in room-temperature molten salts? 

Ionic liquids are a subject of intense interest in many energy applications, including batteries, solar cells, supercapacitors, and processing nuclear waste. Using ionic liquids in such applications involves exposing them to extreme environments and ionizing radiation. Fully harnessing the potential of ionic liquids under these conditions requires a fundamental understanding of how they behave in the presence of excess charge, and how excess charges interact with the liquid itself. Using ultrafast pump-probe spectroscopy, pulse radiolysis, and femtosecond stimulated Raman spectroscopy, we can generate excess charge in the form of excited electrons and watch their subsequent temporal evolution, as well as the structural evolution of the ionic liquid in response to the electron as it relaxes in time. We are particularly interested in how impurities affect this process, and how electron dynamics and reactivity depend on the specific cations and anions in ionic liquids. 

The presence of organic pollutants - such as per- and polyfluoroalkyl substances, or PFAS - in water sources has been a growing concern for their impact on the environment and has highlighted the importance of water remediation strategies. Photocatalytic processes can be utilized in the bond breakage of these persistent organic pollutants, yet there is still more to be known about the electron transfer mechanisms and reaction products. Through the use of ultrafast pump-probe spectroscopy, our group aims to investigate the dynamics of electron cascade pathways in aqueous systems and apply this to understand the fundamental mechanisms involved in the destruction of PFAS.